This invention relates to a process for producing an olefin oxide, more particularly to a process for producing an olefin oxide by oxidizing a corresponding lower olefin with a molecular oxygen in the gas phase in the presence of a catalyst.
Olefin oxides are very important in industry as industrial chemicals and intermediate materials for synthetic resins and rubbers, and various processes have been proposed for oxidizing lower olefins with molecular oxygen in the gas phase in the presence of a catalyst.
Known are, for example, processes using a silver catalyst (Japanese Patent Application Kokoku No. 53-39,404; Japanese Patent Application Kokoku No. 53-12,489; U.S. Pat. No. 4,859,786 and the like), using a copper phosphate-potassium catalyst (J. of Chemical Society, Japan, 1978., 468), using a uranium dioxide catalyst (Japanese Patent Application Kokoku No. 48-27,281), a thallium oxide-cobalt oxide catalyst (Japanese Patent Application Kokoku No. 49-39,962) and the like. However, all these processes produce as by-products large amounts of carbonyl compounds such as carbon dioxide gas, aldehydes, ketones and the like, so that they have such a problem that the selectivity of olefin oxide is low.